Attempts to use Spitzer to detect the transits of SuperEarths will "Start with the HARPS data base [K < 7; now approaching 40 and growing] of solar type stars with radial velocity planets having minimum masses in range 2-20 Earth masses and probabilities of ~2.5-to-15% of being in transiting orbits."

A Survey for Wide Substellar Companions in the Solar NeighborhoodLuhman, Kevin; Fazio, Giovanni; Hora, Joseph; Stauffer, JohnSpitzer Proposal ID #60046We propose to obtain IRAC images of 328 stars, brown dwarfs, and white dwarfs in the solar neighborhood that have been observed previously with IRAC. By combining the data at these two epochs, we will search for wide (>100 AU) substellar companions through their common proper motions with the primaries. The detection limits will reach up to 100 times fainter than the faintest known T dwarfs. These observations will comprise the deepest survey for wide companions to nearby stars that is possible with any current or planned telescope, providing the best available opportunity for finding brown dwarfs cooler than known T dwarfs, such as the as-of-yet-undiscovered Y dwarfs.

The Spitzer Exoplanetary Atmosphere SurveyHarrington, Joseph; Bakos, Gaspar; Cameron, Andrew Collier; Deming, Drake; Fischer, Debra; Fortney, Jonathan; Gillon, Michael; Hellier, Coel; Iro, Nicolas; Laughlin, Gregory; McCullough, Peter; Pollacco, Don; Queloz, Didier; Seager, Sara; Stevenson, Kevin; Tinetti, Giovanna; Wheatley, PeterSpitzer Proposal ID #60003We propose a Target of Opportunity (ToO) program to observe photometric eclipses and transits of extrasolar planets. Spitzer eclipses are the most fundamental (and in many cases the only) direct exoplanetary measurements possible with current instrumentation; transits measure the radius and eclipses the intrinsic fluxes from these worlds. We will populate a figure of predicted equilibrium vs. observed brightness temperatures, which is starting to show patterns indicating different classes of atmospheric behavior. The observations will constrain models of composition, chemistry, and atmospheric dynamics on each planet. The events will also inform follow-on work with other telescopes for the brightest targets. Based on discovery statistics, 25-35 new, observable, transiting planets will be announced in 2009, and somewhat more in 2010. Also, a number of known planets with good predicted signal have not yet been observed. We will publish digital lightcurves with journal articles and submit them for archiving. No comparable opportunity to observe exoplanets will be available until JWST.

Cool, spatially resolved substellar and exoplanetary analogues at white dwarfsBurleigh, Matt; Farihi, Jay; Holberg, Jay; Mullally, Fergal; Steele, Paul; von Hippel, TedSpitzer Proposal ID #60161We propose to obtain second epoch IRAC 4.5 micron images of 87 nearby white dwarfs that were originally observed at the same wavelength during the first two cycles of the Spitzer mission. By combining the data at these two epochs, we will search for spatially resolved T and sub-T-type brown dwarf, and massive planetary companions via common proper motions with their primaries. These observations will comprise the deepest survey to date for wide substellar and planetary-mass companions to white dwarfs in the solar neighborhood. Owing to the known distance and age of each white dwarf, any companions identified in this program would provide a benchmark for examining evolutionary models at ages from a few 100 Myr to several Gyr. This survey will also provide the best statistical limits yet on the frequency of such objects at white dwarfs and their intermediate mass, main-sequence progenitors.

Exoplanet HAT-P-11b Secondary Transit ObservationsBarry, Richard; Deming, Drake; Bakos, Gaspar; Deming, L. Drake; Harrington, Joseph; Madhusudhan, Nikku; Noyes, Robert; Seager, SarahSpitzer Proposal ID #60063We propose to conduct secondary eclipse observations of exoplanet HAT-P-11b, recently discovered by proposal Co-Investigator G. Bakos and his colleagues. HAT-P-11b is the smallest transiting extrasolar planet yet found and one of only two known exo-Neptunes. We will observe the system at 3.6 microns for a period of 22 hours centered on the anticipated secondary eclipse time, to detect the eclipse and determine its phase. Once the secondary eclipse is located, we will make a more focused series of observations in both the 3.6 and 4.5 micron bands to fully characterize it. HAT-P-11b has a period of 4.8878 days, radius of 0.422 RJ, mass of 0.081 MJ and semi-major axis 0.053 AU. Measurements of the secondary eclipse will clarify two key issues; 1) the planetary brightness temperature and the nature of its atmosphere, and 2) the eccentricity of its orbit, with implications for its dynamical evolution. A precise determination of the orbit phase for the secondary eclipse will also be of great utility for Kepler observations of this system at visible wavelengths.

Dynamic atmosphere of the eccentric and massive planet XO-3bMachalek, Pavel; Burrows, Adam; Deming, Drake; Hora, Joseph L.; Johns-Krull, Christopher; McCullough, PeterSpitzer Proposal ID #60058We propose to observe the extended duration (63.0 hours) phase light curves spanning the transit and secondary eclipse of the exoplanet XO-3b, which has a period of 3.19 days, in the 3.6 and 4.5 micron IRAC bands to study the presence of a thermal inversion in its stratosphere and determine the phase variability of the planetary emission temperature. Full phase 3.6 and 4.5 micron photometry will allow us to constrain the longitudinal variation of the XO-3b emission, determine the day-night side heat circulation as well as constrain the presence of any hot-spots on the surface. XO-3b is an unique planet with a high mass Mp D 12.5 MJup, which is close to the deuterium burning limit and so far has the highest observed surface gravity, g D 209 m.s^-2 amongst the known transiting planets. Its orbit has eccentricity e D 0.287, which causes stellar irradiance to vary three-fold over the entire orbit. Unique to XO-3b, the planet revolves around the star on an almost polar orbit with a 70 +/- 15 deg inclination angle relative to the stellar equatorial plane . Of the 11 transiting planets with measured Rossitter-McLaughlin effect, XO-3b is the only one with a nearly polar orbit, thus XO-3b represents a new orbital mode of transiting Hot Jupiters, which in principle would allow us to constrain the latitudinal distribution of the thermal emission from the planet, in addition to the longitudinal thermal distribution. This proposal is a follow-up to the approved Cycle-5 Cold Spitzer DDT program OX3B 'Thermal Inversion in the atmosphere of XO-3b', which investigates the secondary eclipse of XO-3b in all 4 IRAC channels.